1. Field of the Invention
The present invention relates to a self-adhesive part of a hook and loop fastener and a method for forming the same and to an apparatus for forming adhesive layers thereon, and more specifically to a adhesive part structure in which at least a pressure-sensitive adhesive layer is formed so as to adhere said part to a base sheet, and a forming method and apparatus thereof.
2. Description of the Related Art
Existing hook and loop fasteners of this type use a hot melt adhesive. The hot melt adhesives are adversely affected by temperature variations and/or do not provide sufficient strength in some applications. On the other hand, organic solvent based adhesives pose environmental problems.
Thus, a preferable type of adhesive is water based adhesives which dissolves or disperses in water. This is because they are environmentally friendly and in the case of some kind of forumulations a high temperature resistance, up to 160.degree. C. can be provided.
However, the advantages of the water based adhesives are offset by the production difficulties.
The fastener part is manufactured as a long roll with the hooks or loops formed on a flexible polymer base material, as is well known in the art. If the water based adhesive is applied to the back surface of the base material in a continuous process, the coated material must be run through a long path to give the adhesive sufficient time to dry. Attempts at speeding up the drying process impair the performance of the adhesive.